Crossbites Flashcards
Name the three local factors for Crossbites
- Dental Crowding
- Habits
- Cleft Lip and Palate
Most common Dental crowding for Anterior Crossbites
Lateral Incisors
An early loss of deciduous second molars can cause crowding…
Of the permanent premolars
What impact does habits have on the dental arch to cause crossbites
- Narrow Upper arch
- Posterior crossbites
- Pressure applied to anterior maxilla= proclined
What trt would be planned for a Thumbsucker for Crossbites
- Digit dissuader ( removable)
- 7/8 years old - as centrals, laterals and perm molars need to be present.
How does a Quadhelix correct for a crossbite?
1.Expands Upper arch
2. Can be used as a dissuader for habits
3. Active - expands and is adjusted
4. Passive - Retention of expanded arch
What is used for Anterior Crossbites?
1.Anterior expansion screws and Z springs
Creates labial movement
2. 3D Expansion screw ( expands and creates Labial movements)
What is used for Posterior Crossbites?
- Midline Screw
2.Coffin Spring - 3D Expansion Screw ( Expands)
What does a bite posterior bite plane do for Crossbites?
- Props open bite
- Stops occlusal Interference
- Allows teeth to move
Name two Functional Appliances used for Crossbites
- Frankel Appliance
- Clarks TB
How does a Frankel Appliance correct Crossbites?
- Buccal Shields reduce the soft tissues
- Allows expansion of arch passively
How does a Clark TB Appliance correct Crossbites?
- Midline screw corrects ant/post arch relationship by Expansion
- Corrects transverse relationship
How do Fixed Appliances correct Crossbites?
- Torquing with rectangle wires - uprights teeth out of crossbite
*Posterior blocks to correct ant crossbites - Elastics - Upper = palatal to Lower = Buccal
- TMA Wires - buccal crossbites - expand arch
How can a Lingual Crossbite be corrected?
- Elastics Lower= lingual to Upper = Buccal
- SS/ TMA Wires - expand lower arch
How does Headgear correct Crossbites?
- The facebow creates expansion of the Upper arch
- Applied to the Intermolar Region
What is RME?
Rapid Maxillary Expansion
What happens with RME?
- Midline Palatal Suture Splits
- Skeletal Expansion
*Expands and corrects crossbites
What is the screw called on a RME and how is it used by the patient?
- Hyrax screw
- activated 4 x a day
- 1mm movement a day
What Retention is needed for RME?
*RME left passively for 3 months
* prevents relapse and allows bony infill
what is important in stabilising and preventing crossbite relapse?
- Overbite - 1/3 coverage
*good intercuspation
Define “Crossbite”
Abnormal relationship between arches
*Buco - palatal
*Buco - Lingual
Define a Posterior Crossbite
BBB
Buccal cusp of the Lower
occludes
Buccally to the upper buccal
cusp
w
m
Define a Lingual Crossbite
BPP
Buccal cusp of the lower cusp
occludes
Paltally to the palaal cusp of the upper teeth
w
m
Unilateral Crossbite
One side
Bilateral Crossbite
Both sides
Skeletal III Crossbites..
- mandible = protrusive
= Buccal Crossbites
= Anterior Crossbites
Skeletal II Crossbites ..
- Mandible is retroclined
= lingual crossbites
Thumbsucking = Posterior crossbites
Narrow Maxilla Crossbites…
- Unilateral and bilateral crossbites
- can be caused by a digit sucker
= buccal crossbites
Mandibular displacements can cause….
Unilateral crossbites due to displacement
How do the soft tissues effect Crossbites?
*Soft tissues can create a narrow Maxilla EG, Thumbsucker, Mouthbreather - changes the positon of the tongue
* Effect the balance between the cheeks and the tongue
What is a Displacement?
When the mandible slides and occludes into a more comfortable position due to interference.
